Subphylum Crustaceans (class Malacostraca)

Question 1

Subphylum crustaceans are?

Answer 1

The nick name for them is that they are insects of the sea.

Question 2

Examples of subphylum crustaceans?

Answer 2

Lobsters, crayfish, shrimps, crabs, barnacles, water flea.

Question 3

Subphylum crustaceans have what?

Answer 3

They have Mandibles that’s why they call them insects of the sea.
They have two mandibles to crush food,
Two Maxillae to shred food, and also have 2 pairs of Antenna.

Question 4

Subphylum crustaceans do they have any sensory organs?

Answer 4

Yes, they have sensory Masticatory and food handling and these are cephalothorax.

Question 5

Explain thorax and abdominal region of subphylum crustaceans?

Answer 5

They have thorax and abdominal appendages for swimming and walking.
🦵 first pair of walking legs is cheliped bear chelae.

Question 6

What is the function of chelicerae and chelae in subphylum crustaceans?

Answer 6

Grasping food, predation, and defense.

Question 7

What is the function of swimmerets in subpHylum crustaceans?

Answer 7

The very first swimmerets of the male Go to the first swimmerets of the female, and transfer sperm.
Swimmerets are for swimming and also for reproduction.
And the swimmerets (appendages) are biramous (branched).

Question 8

Subphylum crustaceans have what at the anterior end?

Answer 8

They have Rostrum.

Question 9

Subphylum crustaceans have what at the posterior end?

Answer 9

They have Telson.

Question 10

Telson of subphylum crustaceans?

Answer 10

Telson is different then horseshoes crab.
It is flat and it allow the animal to swim in water, it is mostly used for balance.

In telson abdomen terminates and anus are found In telson just like HORSESHOE CRAB🐎 👞 🦀.

Question 11

Uropods, and tail fan in subphylum crustaceans?

Answer 11

These two are used for balance.

Question 12

Body structure of subphylum crustaceans?

Answer 12

Carapace:- it covers the cephalothorax.
Tergum:- exoskeleton plates on posterior (back) of the animal.
Sternum:- plates on ventral side.

Question 13

Coelom of subphylum crustaceans?

Answer 13

Coelom is around the excretory organs and gonads.

Question 14

Muscles of subphylum crustaceans?

Answer 14

Their muscles are striated.
They have flexor muscles which draw a part toward the body.
They have extensor muscles which straighten them out.

These both muscles work antagonistic (opposite) to each other, so the animal can move.

Abdominal flexors muscles of crayfish allow it to swim backward so as to escape predators with strong burst of speed.

Question 15

They have what system and what about their blood?

Answer 15

They have open circulatory system, and their blood have hemolymph.

Question 16

What is the class that we are gonna study in subphylum crustaceans?

Answer 16

Class Malacostraca.

Question 17

Special about class Malacostraca?

Answer 17

They are the largest class,

Question 18

Organism in class Malacostraca?

Answer 18

Astacus Astacus, cray fish.

Question 19

Structure of classs Malacostraca?

Answer 19

They have gills which are like feather 🪶.
They have mandibles for butting food.
They have large cheliped for offense, defense, food catching and handling.

Question 20

Blood of class Malacostraca?

Answer 20

Their blood have the copper and it’s blue color that’s why they call the, hemocyanin.

Question 21

Stomach of class Malacostraca?

Answer 21

Stomach have cardiac chamber and pyloric chamber.

Question 22

Eyes of class Malacostraca?

Answer 22

They have two compound eyes.
Cornea of eye is divided into facets.

Question 23

Antenna of class Malacostraca?

Answer 23

They have two antennae (large) and two antenules (small).
Subphylum chelicerata do not have antenna.

Question 24

At the based of the antenna of the class Malacostraca they have?

Answer 24

They have Statocyst sac (and inside of statocyst they have statolyth) which is used for balancing.
They have sac underneath of antenules which are called statocyst.

Green gland is also at the base of Antenules, and green gland is part of excretory system.

Question 25

First pair of walking leg of class Malacostraca?

Answer 25

It is called cheliped.

Question 26

Cephalothorax is covered by?

Answer 26

Exoskeleton carapace.

Question 27

Another name for green gland is ?

Answer 27

It is Antennal gland.

Question 28

What s the order in class Malacostraca?

Answer 28

Order Isopoda.

Question 29

Order isopoda?

Answer 29

One of the true terrestrial crustaceans that also have marine and freshwater forms.

Dorsoventrallly flattened, lack carapace and have sessile compound eyes 👀.
First pair of thoracic limbs are maxillipeds while the remaining thoracic limbs lack exopods.

Question 30

Important information of crustaceans?

Answer 30

Not all of them are equating some of them are also terrestrial.

Question 31

Common land froms of crustaceans include?

Answer 31

Sow bugs, pill bugs, and wood lice that lives under stones and in damp spaces.

Question 32

Brief survey of crustaceans?

Answer 32

Even though terrestrial the isopods cuticle lack effective protection of insects cuticle to conserve water such that generally have to live in moist habitats.

Some isopods are highly modified as parasites of fishes or crustaceans while some grow to larger sizes and live in depth.

Question 33

Homocoel and function?

Answer 33

It is the major space in arthropods that came from persistent blastocoel which is filled with blood 🩸.

Coelomic compartments remain as end sacs of excretory organs and space around gonads.

Question 34

Copepods?

Answer 34

Scientific name (cyclops)

A copepod is an intermediate host of Guinea worm. Dracanculus medinensis. (Come out from leg).

L3 of dracanculus medinensis is inside of the copepod (cyclops)

When it go to stomach copepod die L3 comes out, and become L4 and adult, and then male female copulate and then female comes out of the leg to got the water (when it sense the moist environment) and then in water it leaves L1, and then L1 again go and find copepod (cyclops).

And then female can go back up to the leg unless the person sees it coming out from leg and remove it.

Copepods
• Cyclops (a copepods an intermediate host of Guinea worms, Dracunculus medinensis)
• No compound eyes
• Major food for whales and fishes
• Some are ectoparasitic

• Barnacles:
  Can be parasitic
  Damage ships and speeding boats
• Daphnia
  • Water flea
  • Diet of many fish and whales
  • Young in brood chamber underneath of carapace.

Question 35

Barnacles?

Answer 35

Fits they thought barnacles are molluscs because of their shell 🐚.

They are monoecious but still practice cross fertilization.
And also do parthenogenesis.

Barnacles damage whale 🐳 and ships 🚢.